On load-carrying vehicles which are provided with a cover, the cover must frequently be rolled up and rolled down for loading and unloading of goods. Previously, the cover was rolled up to form a roll and attached by means of lugs a distance up on the frame supporting the cover. This is an inconvenient and time-consuming operation, and in recent years rolling-up means have therefore been developed which consist of a box attachable to the top of the frame or to the cover stanchions and containing a roller which resembles a roller blind rod. Such an arrangement greatly facilitates rolling-up of the cover, but suffers from the disadvantage that it must be detached and taken down when dismantling the cover frame, or if the cover is damaged. Moreover, the cover must be guided such that its vertical edges are kept perpendicular to the box to prevent wedging of the cover portion while being rolled up. A further disadvantage is that the box takes up a great deal of space, whether the cover is rolled up or lowered to its position of use.